Steam-boiler



(HoModeL) 3 Sheets-sheaf, 1.

H. A. LAUGHLIN. STEAM BOILER.

No.490,119i Paien tedJaJn. 17,1893. FIG-I- I 1 3 Sheets-Sheet 3.

Patented Jan. 17, 1893.-

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WITNESSES:

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HENRY A. LAUGHLIN, OF PITTSBURG, PENNSYLVANIA.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 490,119, dated January17, 1893.

Application filed September 14, 1892. Serial No. 445,880 (No model.)

To all whom it may concern:

Be it known that I, HENRY A. LAUGHLIN, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented or discovered a certain new and usefulImprovementin Steam- Boilers, of which improvement the following is aspecification.

The object of my invention is to provide a tubulous or water tube steamboiler, of

' simple, strong, and comparatively inexpensive construction, in whichalarge amount of grate area and direct heating surface may be affordedwithin small compass, without involving the employment of the largenumber of joints and connecting elements ordinarily used in boilers ofthis type, as well as to render all portions of the structure readilyand conveniently accessible for purposes of cleaning, repair or renewal,toinsure a free, rapid, and continuous circulation of water, and toafford ample facilities for the delivery of dry steam.

To this end, my invention, generally stated, consists in the combinationof two end casings or legs, a steam receptacle connected theretoadjacent to their upper ends, inclined water tubes connecting said endcasings, and a diaphragm or circulating plate located in one of said endcasings above the lower ends of the water tubes.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure 1 is a vertical longitudinalsection, at the line or, so, of Fig. 2, through asteam boilerillustrating a form of embodiment of my invention; Fig. 2, a front viewof ihesame, and; Fig. 3, arear view, partly in section at the line y, 3of Fig. 1.

In the practice of my invention, I provide a front and a rear end casingor leg, 1, 2, each of which is of substantially rectangular form, and isconstructed similarly to the water legs of ordinary tubular boilers,that is to say, formed of sheets set at a proper distance apart toprovide an intermediate water space, and connected and braced, asagainst internal pressure, by socket bolts, or by screw stays 3, asshown, the casings being closed at bottom by mud rings, or, as shown, bychannel plates 4:, and being closed at top, (except where theycommunicate with a steam drum or drums, as presently to be described) bysimilar plates 5, and being also closed at their sides. The casings 1and 2 are set at such distance apart as to afford space between them fora fire and combustion chamber of the length desired, and may, ifdesired, be connected by longitudinal tie rods. A fire grate 7, which,in this instance, is composed of grate bars of the ordinary form,extending longitudinally from one casing to the other, but which may, ifdesired, be a water grate, is supported on bearers 8, above the lowerends of the casings, which extend downwardly for a sufficient distanceto provide a space removed from the direct action of the fire, for thedeposition of separated impurities, which may be discharged, as fromtime to time required, by suitable blow oft cocks 9.

The space between the end casings is closed, at its sides, by wallswhich may, in stationary boilers, be of brick, or, in the case of marineor portable boilers, be formed of light sheet metal, lined with firebrick or tile, and cased with wood or any suitable and preferrednonconducting covering. The fire and combustion chamber, formed by thespace between the casings above the grate 7, is closed at top by a capplate 10, provided with an exit fine or stack 11, and access to the firechamber is bad through one or more openings 12 in the front casing,located above the grate and provided with the usual fire doors 13. Anash pan 14 is located below the grate, and ash pan doors 14, at thefront thereof, are provided for the regulation of draft and the removalof ashes.

The end casings l and 2 are connected, at lower and higher levelsrespectively, by inclined water tubes 15, which are secured, at theiropposite ends, to, as by being expanded into, the inner sheets of therespective sections, and which thereby establish comm unication betweenthe water spaces of the two casings. The Water tubes 15 are preferablyarranged in vertical rows of two or any desired greater number, threebeing shown in each vertical row in the drawings, and with analternately opposite inclination of the respective vertical rows. Itwill be obvious that the number of tubes or of vertical rows, and thenumber of tubes in a vertical row, may be varied in the discretion ofthe constructor, in

accordance with the proportions of width and height of the boiler whichmay be adopted in different cases. Removable plates 16 are inserted inand secured to the outer sheets of the casings 1, 2, opposite the endsof the tubes 15, said plates closing openings in the sheets for theinsertion of the tubes, and of an expanding tool for securing the tubesin position in the sheets, as also for admitting access to the tubeswhen desired for cleaning or re-' moval. In order to enable the tubes 15to be securely expanded inthe inner sheets of the casings, as well as topromote circulation, as hereinafter described, the inner sheets may bebent outwardly and inwardly opposite the lower and upper ends,respectively, of the tubes, as shown in Fig. 1, so that their surfaceswill be perpendicular, or approximately so, to the tubes, at each endthereof.

In order to provide proper and ample steam liberating surface and steamchamber volume, the casings 1 and 2 are, near their upper ends,connected to and communicate with a steam drum or drums, in which thenormal water level is maintained. In the instance shown, a series ofcylindrical drums 20 is employed, thereby affording a material increaseof liberating surface, as compared with a single one, without involvingthe weakness due to the necessarily larger diameter of the latter. Thedrums 20 extend across the combustion chamber, which incloses theirlower portions between the end casings, and the drums may be riveted toflanges turned on the inner and outer sheets of the casings 1 and 2, orbe connected thereto by angle irons. The steam supply pipe 22, leadingto the engine, is provided with the usual stop valve 23, and is, in thisinstance, shown as connected to a supplemental steam drum 20, whichextends transversely to the drums 20, and is connected thereto by shortpipes 24.

A diaphragm or circulating plate 25 is fitted between the inner andouter sheets of each of the end casings 1 and 2, a short distance abovethe lower ends of the upper rows of water tubes 15, said plates beingpreferably, as shown, located between the inwardly and outwardly bentportions of the inner sheets of the casings, and therefore at or nearthe narrowest portions of the water spaces.

The circulating plates extend horizontally.

across the casings from points between the outer rows of tubes and theadjacent ends of the casings, and are then downwardly prolonged, at oneor both ends, to a level adjacent to, and preferably below, that of thegrate, a vertical passage or passages, one of which is seen on the rightof Fig. 3, being thus provided between the downwardly extending portionor portions of each circulating plate and the adjacent end or ends ofthe casing. In the instance shown, the circulating plates 25 aredownwardly extended at both ends,but if so extended at one end only,their horizontal portions should extend to the opposite ends of thecasings. The circulating plates may be'connected to the inner and outersheets in any suitable manner, and are here shown as provided with aseries of sockets 27, through which passes a line of screw stays 3,connecting the inner and outer sheets and securing the circulatingplates thereto.

WVhen located as above described, the circulating plates 25 act tointercept the upward passage of currents of water in the end casingsbeyond the lower ends of the upper water tubes 15 of each vertical row,and to defleet said currents into the tubes, through which they pass,exposed to the direct action of the fire, and are, by reason of theupward inclination of the tubes, and of their tendency to ascend whenheated, delivered, at a higher level, into the water spaces of theopposite casings, being replaced by currents of cooler water, whichdescend, through the spaces between the downward projections of thecirculating plates and the ends of the casings, and thereafter ascend,through the water spaces below the horizontal portions of thecirculating plates, by which they are in turn deflected into the lowerends of the water tubes. The inclined portions of the inner sheets andthe circulating platesprovide receiving spaces diminishing in capacityfrom bottom to top, and delivery spaces increasing in capacity frombottom to top, thereby correspondingly promoting the ingress and egressof water to and from the tubes.

Feed water pipes 26, provided with ordinary check valves, and adapted tobe connected to a pump or injector, are led into the casings 1 and 2,with their discharge ends opening thereinto below the diaphragms orcirculating plates 25, and in order to impart heat to the entering feedwater, as well as to assist in cooling those portions of the casings inwhich it is desired that a downward traverse of water shall take place,the feed pipes 26 may, as shown, enter the casings 1 and 2 at their topsand extend downwardly through the same to points below the ends of thedownward portions of the diaphragms, and then be extendedhorizontallytoward the center lines of the casings.

It will be obvious that as an alternative and equivalent construction,the diaphragms 25 may, if desired,be extended entirely across thecasings1and2,and communicationestablished for the passage of water fromtheir upper to their lower sides by outsidepipes, connected to thecasings above and below the diaphragms, into which connecting pipes thefeed water pipes may be led. The construction shown is, however, deemedpreferable,in the particulars of being within the requirements of a selfcontained boiler, and of affording ample space for the downward passageof water, in the normal and desired circulation thereof during steamgeneration.

While, in the construction herein shown, the tire chamber is providedwith a lower fire grate for the combustion of solid fuel, such firegrate is not an essential of my invention,

and is not employed in cases where waste gases from furnaces, or othergaseous fuel, is desired to be utilized in the generation of steam.

In the operation of a boiler in which the essential elements of theconstruction above described are embodied, the action of the radiantheat of the ignited fuel upon the grate, and the heat of the products ofcombustion thereof which pass upwardly to the stack 11, is exerteddirectly upon the inner walls of the end casings 1 and 2, the surfacesof the water tubes 15, and the lower portions of the drums 20. The waterin the end casings below the circulating plates, and in theinclinedwater tubes 15, as it becomes heated, ascends through the water tubes,and is delivered to the portions of the end casings above thecirculating plates, and thence to the drums 20, its place being suppliedby colder water, which descends in the casings through the passagesbetween the downward projections of the circulating plates 25 and theadjacent ends of the casings, these passages being preferably formed, asindicated in the drawings, by extensions of the casings beyond the grateand side walls of the fire chamber, so that they are not exposed to thedirect heat of the fire. As the cooler water passes under, and entersthe water spaces on the inner sides of the downward projections of thediaphragms 25, it is heated, and ascending through said spaces, entersthe lower or receiving ends of the water tubes, being prevented frompassing above the upper tubes of the vertical rows by the horizontalportions of the diaph'ragms, as before explained. The active circulationthus instituted is promoted by the heat imparted to the rising currentsof water in their passage through the inclined water tubes, and isinsured by the delivery of the feed water into a portion of the boilerfrom which its natural and unopposed tendency is to ascend and pass intothe receiving ends of the water tubes.

My improvement is particularly adaptable to marine service, and toconditions where the rapid and safe generation of steam of high pressureis required to be effected within comparatively limited space. It willbe seen that under a construction substantially as above described,arapid and constant natural circulation of water may be effected, with acorresponding evaporative efficiency, and that any desired amount ofgrate and heating surface permittedby determined circumscribing limitsmay be provided. A further feature of substantial practical ad vantageis the avoidance of the numerous tube joints ordinarily found in boilersof this type, and which are frequently so located as to be rapidlydeteriorated by the direct action of the fire, and to be difficult ofaccess for removal and repair. The only tube joints necessary under myimproved construction are those made with the inner sheets of the endcasings, which are readily and securely made by expanding,

and are conveniently accessible without disturbing any other members, bythe removal of the oppositely located plates in the outer sheets. Thelarge area of liberating surface aiforded by the drums, and the directconnection of the latter with the end casings are, further, of materialadvantage in the prevention of priming, by promoting the delivery of drysteam.

I claim as my invention, and desire to secure by Letters Patent:

1. The combination, in a steam boiler, of two end casings or legs, anupper steam receptacle connected to said casings, inclined water tubesconnecting said casings, and a diaphragm or circulating plate located inone of said casings above the lower ends of the water tubes,substantially as set forth.

2. The combination, in a steam boiler, of two end casings or legs, anupper steam receptacle connected to said casings, oppositely inclinedwater tubes connecting said casings, and a diaphragm or circulatingplate located in each of said casings between the lower ends of thetubes which are inclined in one direction and the upper ends of thetubes which are inclined in the other direction, substantially as setforth.

3. The combination, in a steam boiler, of two end casings or legs havingportions of their inner sheets inclined relatively to their outersheets, an upper steam receptacle connected to said casings, inclinedwater tubes connected at opposite ends to the inclined portions of theinner sheets of the casings, and diaphragms or circulating plateslocated in each of said casings above the upper and below the lowerends, respectively, of the water tubes, so as to provide receivingspaces diminishing upwardly in capacity, and delivery spaces increasingupwardly in capacity, substantially as set forth.

4. The combination, in a steam boiler, of two end casings or legs, anupper steam receptacle connected to said casings, inclined water tubesconnecting said casings, a diaphragm or circulating plate located in oneof said casings above the lower ends of the water tubes, a water passageconnecting the spaces above and below the circulating plate, and a feedwater pipe leading into the space below the circulating plate,substantially as set forth.

5. The combination, in a steam boiler, of two end casings or legs, anupper steam receptacle connected to said casings, inclined Water tubesconnecting said casings, a diaphragm or circulating plate located in oneof said casings above the lower ends of the water tubes, a downwardlyprojecting extension connected to either or both ends of the circulatingplate and forming the inner wall of a water passage connecting thespaces above and below the horizontal diaphragm, and a feed water pipeleading into the space below the diaphragm, substantially as set forth.

6. The combination, in a steam boiler, of

two end casings or legs, an upper steam receptacle connected to saidcasings, an interposed combustion chamber of less width than saidcasings, inclined Water tubes connecting said casings, a horizontaldiaphragm or circulating plate located in one of said casings above thelower ends of the water tubes, a downwardly projecting extensionconnected to either or both ends of the circulating plate and formingthe inner Wall of a water passage in the portion of the casingprojecting beyond the combustion chamber, which passage connects thespaces above and below the horizontal circulating plate, and a feedwater pipe leading into the space below the diaphragm, substantially asset forth.

In testimony whereof I have hereunto set my hand.

HENRY A. LAUGHLIN. \Vitnesses:

J. SNoWDEN BELL, F. E. GAITHER.

